It has a link to the NATS-immobiliser system. If the radio doesn't receive the unique data of its original car, it goes to the "SECURE" mode.
Drive to a Nissan dealer and ask them if they can sort it out. Most likely the radio will need to be sent to a Clarion service to be made "NEW" so it will read and store the new car unique data.
Or contact a decoding company, they can reprogram it.
A.R.S., December 2012
